Adolescents who are maltreated are at elevated risk for developing internalizing problems and externalizing problems. However, not all maltreated adolescents are equally vulnerable to developing mental health problems. Understanding factors that differentiate between those who develop mental health problems and those who do not could lead to more effective interventions for this population. To date, most of the research on the developmental course of internalizing and externalizing problems in maltreated children has been conducted using variable-centered approaches, which assume all individuals come from the same population. Variable-centered approaches are not well suited for identifying clusters of individuals in a population who have distinct developmental trajectories or distinct profiles of internalizing and externalizing problems. Consequently, interventions based on findings from variable-centered studies may not meet the needs of subpopulations with differential developmental courses, etiologies and manifestation of symptoms. The proposed study will address this shortcoming by using person-centered approaches (i.e., growth mixture modeling and latent transition analyses) to model heterogeneity in internalizing and externalizing problems in a sample of 1179 young adolescents (mean age at first wave was 12.8 years) drawn from the National longitudinal Study of Child and Adolescent Well-Being (NSCAW). NSCAW is comprised of a national probability sample of children on the rolls of child protective services who were followed up at 12, 18, and 36 months after baseline. The aims of the project are: (1) To identify clusters (subgroups) of young adolescents who have different internalizing and externalizing trajectories and to investigate whether socio environmental factors (e.g., parent-child relations or peer relations) predict trajectory membership. (2) To identify clusters of adolescents who have distinct patterns of either internalizing or externalizing symptoms or who show a co-occurrence of these symptoms, and to explore the extent to which socio environmental factors are related to change in the pattern of symptoms over time. PUBLIC HEALTH RELEVANCE: Adolescents who are maltreated are at elevated risk for developing internalizing problems (e.g., depression) and externalizing problems (e. g., conduct disorder). However, not all maltreated adolescents are equally vulnerable to developing mental health problems. Understanding factors that differentiate between those who develop emotional and behavioral problems and those who do not could lead to effective interventions for this population.